Estimation of carbon stock changes incorporating agricultural land-use conversion scenarios for producing palm oil-derived biofuels in Malaysia.

The area of oil palm plantations in Malaysia is expanding to fulfil a high demand for palm oil around the world including for producing palm oil-derived biofuels. Planting and expanding oil palm plantations have led to conversion of various land-uses. This study aims to estimate the carbon stock changes (ΔCS) due to conversion of agricultural land-uses, such as rubber plantation, coconut plantation, cocoa plantation, rice field, and black pepper farm to oil palm plantation based on soil organic carbon stock as well as vegetation carbon stock information. The results show that land-use conversion scenarios that changed carbon stock negatively (increased carbon stock) the most was rice field to oil palm plantation (ΔCS: - 334.83 ± 10.78 t CO2-eq ha-1) followed by black pepper farm to oil palm plantation (ΔCS: -268.67 ± 11.40 t CO2-eq ha-1) and coconut plantation to oil palm plantation (ΔCS: -42.67 ± 10.78 t CO2-eq ha-1). Meanwhile, land-use conversion scenarios that changed carbon stock positively (decreased carbon stock) the most was conversion of tropical primary forest to oil palm plantation (ΔCS: 283.97 ± 3.11 t C ha-1), followed by rubber plantation to oil palm plantation (ΔCS: 734.46 ± 10.82 tCO2-eq ha-1) and cocoa plantation to oil palm plantation (ΔCS: 11.39 ± 10.8 t CO2-eq ha-1). Carbon stock changes were significantly different between different groups of conversion age for all land-use conversion scenarios. However, rubber plantation was the only agricultural land-use investigated in this study that indicates no carbon savings after more than 20 years conversion to oil palm plantation. Findings from this study suggested that careful selection of agricultural land-use conversion has to be considered in future oil palm plantation development so as to ensure sustainable energy supplies production. [ABSTRACT FROM AUTHOR]